Based on circadian rhythms experimental results of the immune system, it is assumed that the adrenal cortical hormone influences the migration and distribution of recirculating T lymphocyte between the lymphoid nodes, the blood and the spleen and the effects of cortical hormone on recirculating T cells in the lymphoid nodes and the spleen are different. A mathematical model of T lymphocyte recirculation considering the role of plasma cortical hormone level is presented. The action strength of the cortical hormone, the parameter ranges and the dependence of the modeling behaviors on parameters are explored. The model can explain stable oscillations of T lymphocytes in different lymphoid tissues and the blood, the numerical results are consistent with immune circadian rhythms experiments.